FIG. 1 is a cross-sectional view illustrating a conventional method of manufacturing a metal-insulator-metal capacitor.
Referring to FIG. 1, a lower metal electrode layer pattern 121 for a MIM capacitor and a lower metal line layer pattern 122 for a metal line are respectively formed on an insulating layer 110 on a semiconductor substrate 100. As an example, the lower metal electrode layer pattern 121 may include a TiN layer 121a and an Al layer 121b. The lower metal line layer pattern 122 may include a TiN layer 122a and an Al layer 122b. Although not shown in the drawing, the lower metal electrode layer pattern 121 and the lower metal line layer pattern 122 can be electrically connected to a lower metal line layer (not shown). An insulating layer 130 is then formed. Next, a trench 140 exposing the lower metal electrode layer pattern 121 in a MIM capacitor region is formed by an etching process using a predetermined mask layer pattern as an etching mask. Then, a dielectric layer 150 is formed over the entire upper surface of the resultant structure formed with the trench 140. A photoresist layer pattern 160 is formed over the dielectric layer 150 to form an etching mask layer pattern for forming a via hole. The photoresist layer pattern 160 includes an opening 161 exposing an upper surface of the dielectric layer 150 at which a via hole will be formed. A via hole 170 exposing the lower metal layer pattern 122 is formed by an etching process using the photoresist layer pattern 160 as an etching mask.
Although not shown in the drawing, the photoresist layer pattern 160 is removed after the formation of the via hole 170, and a metal layer (not shown) such as a tungsten layer is formed over the entire upper surface of the resultant structure after removing the photoresist layer pattern 160. In addition, if a planarization process is performed such that a surface of the dielectric layer 150 is exposed, an upper metal electrode layer is formed within the trench 140 in the MIM capacitor region, and a via contact is formed within the via hole 170 in a metal line region. Then, by performing deposition and patterning of a metal layer, an upper metal layer pattern, which is electrically connected to the via contact in the metal line region and the upper metal electrode layer in the MIM capacitor region, is formed by interposing a barrier metal layer.
However, such a conventional method of manufacturing the MIM capacitor may have the following problem. In the process of forming the photoresist layer pattern 160, a thickness of the photoresist layer pattern 160 at an upper edge portion of the trench 140 may be relatively thinner, because of the existence of the trench 140, than a thickness at other portions. In such a case, the portion of the photoresist layer pattern 160 near the upper edge portion of the trench 140 may be removed by the etching process for forming the via hole 170, thereby forming a groove 180 destroying the insulating layer 130. Furthermore, the groove 180 may penetrate the insulating layer 130 thereby exposing the lower metal electrode layer pattern 121. This problem may be solved by increasing the thickness of the photoresist layer pattern 160, but the high degree of integration of many semiconductor devices limits the amount the thickness of the photoresist layer pattern 160 may be increased.
To clarify multiple layers and regions, the thickness of the layers are enlarged in the drawings. Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used in this patent, stating that any part (e.g., a layer, film, area, or plate) is in any way positioned on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, means that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween. Stating that any part is in contact with another part means that there is no intermediate part between the two parts.